Control of the architectural assembly of octacalcium phosphate crystals indenatured collagenous matrices

Xerogels, obtained by evaporating a water solution of gelatin, were used as templates for the growth of crystal assemblies of calcium phosphate. Octac alcium phosphate (OCP) crystals were grown inside the gelatin xerogel by di ffusion of solutions of calcium and phosphate ions into the gelatin films f rom opposite ends. The structure, morphology and orientation of the crystal s grown on the surfaces and inside the gelatin films were studied by optica l and scanning electron microscopy and X-ray diffraction. OCP was the uniqu e detectable crystalline phase. The crystals preferentially grew as thin pl ates elongated along their c axes with large {100} faces parallel to the sh eets of gelatin films. When the gelatin films were uniaxially deformed the OCP crystals grew with their c axes almost parallel to the direction of def ormation. According to a mechanism of templated nucleation, a structural mo del for the ordered growth of OCP on the portions of triple helical collage n molecules has been proposed.